Current May US benzene spot prices were at $4.15-4.20/gal FOB (free on board) HTC (Houston-TexasCity), steady from Tuesday, aromatics traders said. The range was up from $3.97-4.03/gal FOB HTC a month earlier, according to global chemical market intelligence service ICIS pricing.

Valero said process units at the Houston refinery went offline due to boiler and steam system problems.

Production is expected back to normal next week, but Valero estimated it will lose about 64,000 bbl/day of gasoline and 44,000 bbl/day of distillate in the meantime.

The Houston refinery was the latest in a string of Valero refinery glitches, which contributed to tightness in the gasoline market and helped pull aromatics prices higher the past two months.

Market participants said a crude unit at Valero’s 295,000 bbl/dayPort Arthur refinery in Texas was down but slated for restart this week.

The company would not comment on day-to-day operations, but said there was no material impact on production at its Port Arthur refinery.

A Houston-based aromatics broker said the additional refinery glitches were not good for the market and helped to push benzene prices higher in April and May.